Last visit was: 18 Nov 2025, 14:08 It is currently 18 Nov 2025, 14:08
Close
GMAT Club Daily Prep
Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track
Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
Close
Request Expert Reply
Confirm Cancel
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 18 Nov 2025
Posts: 105,355
Own Kudos:
Given Kudos: 99,964
Products:
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 105,355
Kudos: 778,062
 [30]
2
Kudos
Add Kudos
28
Bookmarks
Bookmark this Post
Most Helpful Reply
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 18 Nov 2025
Posts: 105,355
Own Kudos:
778,062
 [7]
Given Kudos: 99,964
Products:
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 105,355
Kudos: 778,062
 [7]
2
Kudos
Add Kudos
5
Bookmarks
Bookmark this Post
General Discussion
User avatar
sumitkrocks
Joined: 02 Jul 2017
Last visit: 22 Aug 2023
Posts: 639
Own Kudos:
870
 [4]
Given Kudos: 333
Location: India
Concentration: Strategy, Technology
GMAT 1: 730 Q50 V39
GMAT 2: 710 Q50 V36
Products:
GMAT 2: 710 Q50 V36
Posts: 639
Kudos: 870
 [4]
1
Kudos
Add Kudos
3
Bookmarks
Bookmark this Post
User avatar
Kinshook
User avatar
Major Poster
Joined: 03 Jun 2019
Last visit: 18 Nov 2025
Posts: 5,793
Own Kudos:
5,508
 [3]
Given Kudos: 161
Location: India
GMAT 1: 690 Q50 V34
WE:Engineering (Transportation)
Products:
GMAT 1: 690 Q50 V34
Posts: 5,793
Kudos: 5,508
 [3]
3
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Given: Odyssey runs from the Trojan Horse, which does not move, to the gates of Troy and back to the Trojan Horse by the same path.
Asked: Was his average speed less than 20 kilometres per hour for the entire journey ?

Let the distance between Trojan horse and Troy be D km and time taken from Trojan horse to Troy be t1 and time taken back to Trojan horse from Troy be t2.
Average speed for the entire journey = 2D/(t1+t2)
v1 = D/t1
v2 = D/t2

(1) Odyssey's average speed from the Trojan Horse to the gates of Troy was greater than 40 kilometres per hour.
v1 = D/t1 > 40 kmph
D > 40t1
Average speed for the entire journey > 80t1/(t1+t2)
If t2 = 0; Average speed for the entire journey > 80 kmh
But if t2 is infinite; Average speed for the entire journey = 0 kmh
NOT SUFFICIENT

(2) Odyssey's average speed from the gates of Troy to the Trojan Horse was less than 10 kilometres per hour.
v2 = D/t2 < 10 kmph
D < 10 t2
Average speed for the entire journey < 20t2/(t1+t2)
If t1=0; Average speed for the entire journey < 20 kmph
But if t2 is infinite; Average speed for the entire journey = 0 kmph
In both extreme case, Average speed for the entire journey < 20 kmph
SUFFICIENT

IMO B
User avatar
MV94
User avatar
Current Student
Joined: 15 Aug 2020
Last visit: 15 Dec 2022
Posts: 54
Own Kudos:
81
 [4]
Given Kudos: 286
Location: United States (OR)
Concentration: Finance, Organizational Behavior
GMAT 1: 770 Q50 V46
GPA: 3.73
WE:Analyst (Mutual Funds and Brokerage)
GMAT 1: 770 Q50 V46
Posts: 54
Kudos: 81
 [4]
3
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
1: does not tell us anything about his speed coming back, insuff. He could run at 40kmph back and it would be, or 0.5kmph back and it wouldn't be.
2: this is sufficient to tell us he cannot run faster than 20kmph. If half the trip is spent running at half the desired speed, one cannot make up the difference in the second leg. For instance, say Troy is 20km away, he would need to complete the round trip in 2 hours to run 20kmph. However, at 10kmph, the first leg takes him 2 hours, meaning no matter how fast he returns, he cannot exceed an average of 20kmph. This is sufficient to tell us he did not average less than 20kmph.

IMO B.
User avatar
avinashiitp
Joined: 11 Dec 2019
Last visit: 01 Mar 2023
Posts: 100
Own Kudos:
73
 [2]
Given Kudos: 79
Location: India
GMAT 1: 710 Q50 V35 (Online)
GMAT 1: 710 Q50 V35 (Online)
Posts: 100
Kudos: 73
 [2]
2
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Average speed formula when distance is constant is 2/(1/x+1/y)

from statement 1 -> y>50
from statement 2 ->x<10

put statement 2 in formula- 20*y/(10+y) or simplify 20/(1+10/y)

which shows statement is sufficient irrespective of y

Hence B
User avatar
bumpbot
User avatar
Non-Human User
Joined: 09 Sep 2013
Last visit: 04 Jan 2021
Posts: 38,586
Own Kudos:
Posts: 38,586
Kudos: 1,079
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
Moderators:
Math Expert
105355 posts
496 posts